Capture selected text from active window

Question

Hi all,

Need on your help on this.

I need to capture the selected text from the current window (be it a browser or any other application), and print it in my c# console application (for now - to keep is simple).

I got some help from the following thread:
http://www.c-sharpcorner.com/Forums/ShowMessages.aspx?ThreadID=46461

But, it gives me an ArgumentOutOfRange exception in the last line (substring operation)

Other ideas / approaches for implementing this are also welcome.

Thanks in advance,

Jd